this is because Facebook is an ad network - you & your friends are the product. Facebook sells your eyes to their customers, and if their customers want to show you flash pre-rolls and interstitials, then that's exactly what Facebook will use. Money talks.

it's job security because if they took your advice and assumed they were smarter than everyone else and just went with what they thought would work... they would have failed abysmally. they would be assigned to cleaning the toilets while someone who knew what they were talking about was put in charge of actually doing it right.

yeah, that's fine if you want your video to work only sometimes, on some devices. and if you don't need pre-rolls, or interstitials, or playlists, or analytics, or you don't care about handling full-screen correctly, or adaptive bitrate.

pop quiz: which versions of firefox support h.264? which protocol suports bitrate streaming on google chrome on windows? on iPad?